Stormwater Glossary

Buffer: A strip of land adjacent to a stream that is not disturbed during construction. Buffers filter stormwater as it flows to surface waters.

Catch basins: Curbside openings that collect rainwater from streets and serve as an entry point to the storm drain system.

Culverts: Pipe or concrete box structure that drains open channels or ditches under a roadway or embankment.

Daylighting: to take a stream out of a culvert and allow it to flow in its natural channel.

Erosion: The detachment and transport of soil or rock fragments by water, wind, ice, etc.

Impervious surface: Surfaces that do not allow rainwater to infiltrate into the soil, including rooftops, parking lots, walkways, dirt and gravel roads, tennis courts, etc.

Runoff: Water from rain, melted snow, or landscaping irrigation that flows over land and into drainage facilities, local creeks, streams and waterways. Runoff often carries pollutants in it.

Service-based fee: Fee for service based on use.

Storm drains: A vast network of underground pipes and open channels designed for flood control, which discharges into waterways.

Stormwater: Rainfall that runs off impervious surfaces. Stormwater enters the storm drain system and eventually empties into lakes, rivers and streams. Unmanaged stormwater can cause water quality problems, streambank erosion and flooding.

Stormwater pollution: Water from rain, irrigation, garden hoses or other activities that picks up pollutants, such as cigarette butts, trash, automotive fluids, used oil, paint, fertilizers and pesticides, lawn and garden clippings and pet waste, from streets, parking lots, driveways and yards and carries them through the storm drain system and straight to waterways.

Stormwater retention/detention pond: A facility designed to detain stormwater runoff for a short period of time before releasing it to surface waters.

Stormwater system: The system built to collect and transport runoff to prevent street and property flooding. Components include drains, culverts, catch basins, stormwater retention ponds. Anything that flows into the storm drainage system flows directly into local creeks, streams, and waterways. Stormwater runoff is not treated like wastewater is; the storm drainage system is completely separate from the sanitary sewer system.

Streambank: A bank or slope immediately adjacent to a stream. Erosion of a streambank can increase the amount of sediment carried by the stream, with serious impacts on the stream's biological systems.

Streambank erosion: Removal of soil particles from a bank slope primarily due to water action. Changes in land use, climatic conditions, ice, debris and chemical reactions can also cause streambank erosion.

Streambank stabilization and restoration: The process of building and rebuilding the banks of streams, creeks or rivers to prevent erosion and filter polluted runoff. Buffers can be planted to help restore a stream bank.

Watershed: An area of land that drains runoff to a particular stream, river, lake or waterway.